1. Field of the Invention
The present invention relates to a printing control apparatus, an image forming system, and a printing control method.
2. Description of the Related Art
In the past, there is an image forming apparatus that stores a clear toner, which is a colorless toner not including a color material, other than toners of four colors CMYK. A toner image formed by such a clear toner is fixed on a recording medium on which an image is formed with the toners of CMYK. As a result, a visual effect and a tactual effect on the surface of the recording medium (referred to as surface effects) are realized. Surface effects to be realized are different depending on what type of toner image is formed with the clear toner and how the toner image is fixed. Some surface effect simply imparts a gloss and other surface effect suppresses a gloss. It is desired to impart a surface effect to only a part of the surface rather than to the entire surface. There is also a demand for a surface effect for forming a texture or a watermark with the clear toner. In some case, surface protection is demanded. There is also a surface effect that can be realized by performing post-processing with a dedicated post-processing machine such as a glosser or a low-temperature fixing machine besides fixing control. In recent years, for example, as disclosed in Japanese Patent No. 3473588, a method of depositing the clear toner only on a desired portion in a part of the surface to impart a gloss is developed.
As disclosed in Japanese Patent Application Laid-open No. 2007-034040, the gloss is affected by surface roughness of the image formed on the recording medium. In other words, the gloss is affected by unevenness of the surface of the recording medium caused by the toners of CMYK. Therefore, a degree of the gloss does not simply increase according to the density of the clear toner.
In order to impart a gloss, it is necessary to control the smoothness of the surface of an image. Therefore, it is necessary to create, according to density values of CMYK concerning pixels to which the clear toner is deposited, image data for forming a toner image by the clear toner.
From the viewpoint of imparting a larger number of types of surface effects, it is desirable that a printing apparatus is mounted with post-processing machines of types determined in advance. However, in some case, a plurality of types of post-processing machines necessary for realizing all the surface effects are not mounted because of various reasons. Therefore, when a part of the post-processing machines are not mounted, a user needs to perform selection or the like of surface effects of realizable types taking into account the configurations of the post-processing machines. However, it is difficult for the user to perform such setting.
Therefore, there is a need for a printing control apparatus, an image forming system, and a printing control method that can impart surface effects by a clear toner to a recording medium, on which an image is formed, without causing a user trouble even when a part of post-processing machines are not mounted.